1. Field of the Invention
The present invention relates to manual feed trays and image forming apparatus including the manual feed trays.
2. Description of the Related Art
Image forming apparatus such as copying machines, facsimile apparatus, printers, and combinations thereof include, apart from a main body feeding cassette for feeding paper that is frequently used, mechanisms including a tray for allowing for the manual feed of paper. The manual feed tray can be used for feeding paper sheets of a size that is not frequently used or special kinds of paper sheets such as postcards and envelopes. In the above-mentioned image forming apparatus such as copying machines, facsimile apparatus, printers, and combinations thereof, one of the goals is to reduce the size of the apparatus so as to provide for space saving.
In order to achieve the above-mentioned goal, when the manual feed tray is not used, the tray is located within the image forming apparatus main body to define a side surface of the image forming apparatus main body, and when the tray is used, the manual feed tray is moved to a sheet feeding position by pulling out the forward end thereof. In order to provide a sufficient stacking surface for supporting the paper, it is common practice to pull out an extension member from the manual feed tray. Since the forward end of the manual feed tray is upwardly inclined, the extension member has a lock mechanism for retaining the extension member at the pulled-out position so as to prevent the extension member from falling off.
FIGS. 16 and 17 illustrate a first prior art example. As illustrated in FIG. 16, when a manual feed tray 101 is not used, the manual feed tray 101 is located in a portion 102a (indicated by the chain double-dashed line) formed in a side surface 102 of an image forming apparatus main body 100. As illustrated in FIG. 17, when the manual feed tray is to be used, a cover member 103 is opened to a sheet feeding position, and a first tray 104 is pulled out of the cover member 103. Further, a second tray 106, folded into a recess 105 of the first tray 104, is swung open around a forward end portion 104a of the first tray 104. As a result, a sheet stacking surface of the manual feed tray 101 is provided.
FIGS. 18 through 21 illustrate a second prior art example. Provided is a manual feed tray 111 having a main body 114 and an extension tray 112. The main body 114 has a guide rib 115 and side restriction grooves 116. The extension tray 112 has a guide rail 113 in the back surface of the extension tray 112. The guide rail is fitted with a guide rib 115 so as to be slidable on the guide rib 115, and both side portions 112a (both side portions in a direction orthogonal to the pulled-out direction) of the extension tray 112 are fitted with side restriction grooves 116 so as to be slidable in the grooves 116. As a result, the extension tray 112 is slidable without being detached from the manual feed tray main body 114. Further, in the manual feed tray 111, when the extension tray 112 is pulled out, positioning protrusions 117 on the back side of the extension tray 112 move over positioning ribs 118 of the manual feed tray main body 114, with the extension tray 112 itself being elastically deformed. When the extension tray 112 is pulled out to a predetermined position (sheet feeding position), the positioning protrusions 117 of the extension tray 112 are received into a positioning recess 120 of the manual feed tray main body 114 and locked therein. When restoring the extension tray 112 to the former position (the position prior to being pulled-out), as long as the operator does not push the forward end side of the extension tray 112 to release the engagement of the positioning protrusions 117 and the positioning recess 120 (i.e., to release the lock), the extension tray 112 is retained at a predetermined position (sheet feeding position), and the extension tray 112 will not be automatically restored to the former position (position prior to being pulled-out).
In the manual feed tray 101 disclosed in the first prior art example, each time the manual feed tray 101 is closed, the user has to move the second tray 106 and the first tray 104 into the storage position, resulting in a bother. When the manual feed tray 101 is moved to the storage position, with the second tray 106 and the first tray 104 being left unmoved, the side surface 102 of the image forming apparatus main body 100 and the first tray 104 abut each other or the side surface 102 and the second tray 106 abut each other, and there is a possibility that the first tray 104, the second tray 106 or the side surface 102 of the image forming apparatus main body 100 can be damaged.
Referring to FIG. 21, the manual feed tray 111 of the second prior art example can be located in the image forming apparatus main body 121. When the user forgets to store the extension tray 112, from the sheet feeding position (position indicated by the chain double-dashed lines), due to the lock mechanism described above, the extension tray 112 is retained in the state when the extension tray 112 is pulled out of the manual feed tray 114. Thus, the extension tray 112 moves to the storage position in the image forming apparatus main body 121 while the extension tray 112 is retained in a pulled-out position. As a result, because the side surface 122 of the image forming apparatus main body 121 and the extension tray 112 abut each other, as illustrated in FIG. 21, there is possibility that the extension tray 112 and the side surface 122 of the image forming apparatus main body 121 can be damaged. Thus, the operator has to ensure that the extension tray 112 is stored every time the operator stores the manual feed tray 111, which is a bother.